getting tubes tied

Rebecca • Married to my high school sweetheart. Currently have 2 children Xavier Cole and Mariah Nicole.
I am strongly contomplating getting my tubes tied. The only thing that holds me back is because I am still so young. I am on my 3rd child and I am only 21. I am in a marriage and all 3 of my kids have the same father. He says he is fine with not having anymore, but I'm constantly thinking what if I want 1 more later. But part of me feels like I would regret if I got pregnant again. This pregnancy was a complete shocker and I don't regret it but I really don't think I'll want more. I don't know if I should go ahead and tell my dr so I can go ahead and sign papers to have it done or what to do. I guess I'm just asking for advice or opinions. I don't know what to do.